1. Field
Example embodiments of the inventive concept relate to wall and floor structures for reducing floor impact sound. More particularly, example embodiments of the inventive concept relate to techniques for reducing floor impact sound in the wall and floor structures by changing a direction of an acoustic wave and dissipating sound energy with a panel having a patterned layer formed using materials having different densities and elastic modulus.
2. Discussion of Related Art
Because of the rapid urbanization, the majority of people live in apartment houses. Therefore, there are many floor noise problems and conflicts are deepening and being raised as social issues.
Floor impact sound of the floor noises is divided into a light impact sound and a heavy impact sound according to the impact characteristics. The light impact sound is an upper register sound of 58bB or less with a light and hard sound, such as dragging a table, garlic clenching, falling objects, etc. The light impact sound has a low impact force and short acoustic duration. The heavy impact sound is a lower register sound, such as sounds of children's beats, footsteps, etc. The heavy impact sound has physical characteristics that impact force is large and acoustic duration is long, and it is difficult to reduce it.
In order to solve the floor noise, shock absorbing materials such as a fibrous mat, a rubber-base mat, or a porous resin mat is used on the floor surface, or a floating floor structure separated from the floor surface is mainly used.
Such the shock absorbing materials and floating floor structures can effectively reduce the light impact sound by about 54%, but the effect on the heavy impact sound is merely about 8%.
It is expected that a column type structure model will be applied to newly constructed apartments to reduce the floor noise. However, the column type structure model is relatively expensive, and it is applied only to newly built houses, so measures against existing apartments are necessary.
As a conventional technique, a patent document 1 provides a building material having an aerogel formed between cardboards on which a plurality of bumps are formed to have an effect on heat insulation, soundproofing, sound absorption, dustproofing and pollutant adsorption. Aerogels having a nano-porous structure between the cardboards are semitransparent, extremely low-density, and are efficient heat insulating materials. Since the flooring materials are closely related to heating, the building material disclosed in the patent document 1 formed of the aerogel having high heat insulation is not suitable as the flooring material. In addition, aerogel is put between the cardboards having many fine pores, and the aerogel is an expensive material. Therefore the building material disclosed in the patent document 1 is not suitable as a flooring material for flooring for soundproof purposes.